Hydrogen production at high Faradaic efficiency by a bio-electrode based on TiO2 adsorption of a new [FeFe]-hydrogenase from Clostridium perfringens

Abstract

The [FeFe]-hydrogenase CpHydA from Clostridium perfringens was immobilised by adsorption on anatase TiO2 electrodes for clean hydrogen production. The immobilized enzyme proved to perform direct electron transfer to and from the electrode surface and catalyses both H2 oxidation (H2 uptake) and H2 production (H2 evolution) with a current density for H2 20 evolution of about 2 mA cm -1 . The TiO2/CpHydA bioelectrode remained active for several days upon storage and when a reducing potential was set, H2 evolution occurred with a mean Faradaic efficiency of 98%. The high turnover frequency of H2 production and the tight coupling of electron transfer, resulting in a Faradaic efficiency close to 100%, support the exploitation of the novel TiO2/CpHydA stationary electrode as a powerful device for H2 25 production.2

Electron transfer and H2 evolution in hybrid systems based on [FeFe]-hydrogenase anchored on modified TiO2

“…clearly shows that all the hybrid systems present a significantly higher activity in H2 evolution with respect to that observed for the TiO2 powders alone.The turnover frequency numbers (TOF) for these systems are as follows: 2.8 ± 0.2 s -1 (TiO2-CpHydA); 4.1 ± 0.1 s -1 (N-TiO-CpHydA2) and 0.6 ± 0.1 s -1 (rd-TiO2-CpHydA). It is remarkable that the TOF observed here are in good agreement with values observed for CpHydA immobilized on anatase electrodes in an electrochemical cell in the dark [57]. This suggests that binding of CpHydA on various TiO2 materials and the electron transfer occur similarly.…”

Oxygen Stability in the New [FeFe]-Hydrogenase from Clostridium beijerinckii SM10 (CbA5H)

“…[3][4][5] Thus, the isolation and characterization of novel [FeFe]-hydrogenases is expected to provide novel important information. 6,7,8 A common feature to all [FeFe]-hydrogenases is oxygen sensitivity: these enzymes are found in strict anaerobic or facultative anaerobic organisms and they are inactivated by molecular oxygen. Oxygen inactivation is a complex mechanism, still under active debate.…”

Recent Enzymatic Electrochemistry for Reductive Reactions

“…Some examples of DET have been reported using single‐walled carbon nanotubes for H 2 ase immobilization . A very recent example of DET was the immobilization of [FeFe]‐H 2 ase from Clostridium perfringens by simple adsorption on anatase TiO 2 electrodes . The reported current density for H 2 production was approximately 2 mA cm −2 with a FE of 98 % (at −0.74 V vs .…”